#include "stdio.h"
int main()
{	     	   
    double term, pi;
    int i;

    pi = 1;

    for (i = 1; i <= 100; i = i + 2) //2
    {	     	   
        term = (double)(i + 1) / i * (i + 1) / (i + 2); //2
        pi = pi * term; //2
    }

    printf("pi=%f\n", pi * 2); //1
    return 0;
}	     	   